CO2 emissions due to the combustion of fossil fuels receive the most attention and the energy sector appears to be the most represented in national inventories, as it is responsible for the prevailing emission quota, equal to approximately 80% of the total recorded. Bioelectrochemical power-to-gas (BEP2G) is a process of (accumulating electrical energy produced from non-programmable renewable sources in the form of hydrogen and/or methane.

Electromethanogenesis is one of the most innovative power-to-gas technologies, in which CO2 is reduced to methane bioelectrochemically, by hydrogenotrophic microorganisms. It cannot be conveniently applied to the recovery of CO2 from the air, in which it is present in too low a concentration, also due to the presence in air of a high concentration of oxygen, which disturbs the anaerobic microbial flora responsible for the process.

With an innovative approach, it was therefore decided to investigate natural gas sources rich in CO2 and poor in oxygen, such as those of geological origin, widely distributed throughout Italy. The development of a new technology, which can be defined as geological electromethanogenesis, can consequently be aimed at the recovery of abandoned areas that suffer the impact of geological gases naturally emitted into the atmosphere. The objective of the research is the scale-up in the field of microbial electromethanogenesis processes tested so far only at laboratory level, with a prospect of significant energy and environmental advantages for the country.

Tuscan territory of Mount Amiata and Larderello, whose impacts due to gases of natural geological origin have been known since the exploitation of boraciferous mines, was selected as as the study area to evaluate a potential application in the field of geological electromethanogenesis.

This report contains a review of the main methods for detecting CO2 emissions, with particular reference to the geochemical techniques that will be used for the characterization of selected sites in the Tuscan territory. In particular, a new type of multiparametric probe is presented, created for the specific purpose of characterizing, from a chemical-physical and microbiological point of view, the soil impacted by geothermal gas emissions.

This probe is an innovative integrated version of a group of electrochemical sensors tested individually in previous measurement campaigns on soils impacted by CO2 flows.

The document is available on the site in Italian